Since you asked, here's one. In "Bad Day at Black Rock," Dean, much as the picture reminds us, declares himself Batman. In Batman vs. Superman, Jeffrey Dean Morgan plays Thomas Wayne in the only scene that's been done more times in the last 15 years than Spider-Man's origin story. You could do something with that!

Yeah, there's a shot of JDM in the trailer. You could go pretty much anywhere with it. Secret Relative fic, Bruce as a Hunter, Dean as Batman and Sam as Nightwing (and Bobby instead of Alfred, because maybe Bruce wouldn't be quite as messed up about family if Alfred were more willing to call him an idjit). Heck, really go nuts and cross Smallville in, too, if you're feeling it. :)